Pressurizing Members Twin screw extruder
A twin screw extruder which includes a twin conical container having a material inlet port, a material extruding port on the opposite side of the material inlet port, and an inner conical wall surface converging toward the material extruding port, a pair of single screw extruder accommodated in the twin conical container, each of the conical screw rotors having a free end adjacent to the material extruding port and a base portion rotatably supported such that the screws of the two rotors intermeshingly rotated in two different directions and a pressurizing device provided in each free end of the screw rotors so as to forcibly keep the free ends of the screw rotors in contact with each other at a predetermined contact pressure so as to overcome a pressure arising from the extruding operation.
Twin conical rotors 1A, 1B are to be rotated with screws thereof meshed with each other. The conical rotors 1A, 1B are supported at the base portions thereof by bearings 2A, 3A and 2B, 3B, respectively, and have free ends at the tips thereof. The conical rotors 1A, 1B are engaged at gears 4A, 4B with each other and driven to be rotated in different directions. A container 5 comprises (i) an inner surface in the vicinity of a twin circular cone which constitutes the locus of rotation of the mountain portions of the screws of the conical rotors 1A, 1B, (ii) a material inlet port 6 disposed on the base portion of the twin circular cone and (iii) a material extruding port 7 at the tip of the container 5. The container 5 is secured to a base stand such that the material extruding port 7 is downwardly inclined.
The twin conical screw extruder in accordance with the present invention comprises no-load pressurizing means arranged such that the rotor tips are pushed to and by each other at a predetermined force at a state where no load is applied to the conical rotors.
The term of "state where no load is applied" refers to the state where a material to be extruded is not present in the extruder container and the internal pressure applied by the material is zero.
According to the present sheet production extruder, the no-load pressurizing means preferably comprises tip pressurizing members fitted to the tips of the shafts of the conical rotors in such a manner as to be adjusted in the positions thereof in the axial directions of the rotor shafts, and adjusting and setting devices of the tip pressurizing members
According to the present single screw extruder, the no-load pressurizing means is preferably formed by means for adjusting the angle formed by the axes of the bearings which support the twin rotors, the means being arranged such that, after the extruder is assembled such that no pushing force is applied to the twin rotors, the angle formed by the axes of the bearings is increased and adjusted such that a predetermined pushing force is applied to the twin screw extruder.